JPS60204736A - Preparation of p-tert-butylbenzaldehyde - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as an intermediate for odorants, agricultural chemicals, etc., industrially at a low cost, by brominating p-tert- butylbenzyl chloride prepared by chloromethylating tert-butylbenzene, and hydrolyzing the resultant bromination product. CONSTITUTION:tert-Butylbenzen is chloromethylated to give p-tert-butylbenzyl chloride, which is then brominated with an equimolar amount of bromine at 100-200 deg.C to afford a p-tert-butylbenzal halide consisting essentially of p-tert- benzal chlorobromide. The resultant p-tert-butylbenzal halide is then hydrolyzed with an about equimolar amount of water at e.g. 105-125 deg.C to give p-tert-butylbenzaldehyde. The unreacted p-tert-butylbenzyl chloride in the bromination reaction is treated with hexamethylenetetramine at 4-4.5pH and oxidized to give the p-tert-butylbenzaldehyde. Thus, the yield can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an industrially advantageous method for producing pt-butylbenzaldehyde.

This substance has recently become extremely useful as an intermediate for flavoring agents or as an intermediate raw material for agricultural chemicals.

The conventional method is to oxidize p-1-butylbenzyl chloride obtained by chloromethylating t-butylbenzene with hexamine or an inorganic oxidizing agent (dichromate, etc.) to produce p-t-butylbenzaldehyde. However, considering the current social and environmental issues, a large amount of expense is required to treat wastewater from hexamine oxidation solution or chromic acid, and this method is not suitable for the current situation. lost.

Another method is to bromine pt-butyltoluene with 2 moles of bromine under various conditions to produce pt-butylbenzalbromide, which is then hydrolyzed to obtain pt-butylbenzaldehyde. .

Regarding method (1), as mentioned above, the yield of chloromethylation and the processing of hexamine oxidation waste liquid or chromium acid waste liquid during production require a great deal of expense, and the manufacturing cost of the product increases; Not economical.

Since the method (2) uses 2 moles of expensive bromine, it cannot be said to be an economically meaningful method.

The present invention provides a method for industrially producing pt-butylbenzaldehyde at low cost. First, as a first step, pt-butylbenzaldehyde is produced by O-methylation of t-butylbenzene.
By brominating butylbenzyl chloride to produce pt-butylbenzal halide and hydrolyzing this, 1 mole of expensive bromine is sufficient, so economically (2
) method is cheaper.

In addition, if pt-benzal chloride is produced from pt-butylbenzyl chloride using chlorine and then hydrolyzed, it should be cheaper because expensive bromine is not used, but this method In this case, the conditions are the same as when D-t-butyltoluene is chlorinated with 2 moles of chlorine, and the hydrogen of the t-butyl group is replaced by chlorine, making it impossible to achieve the objective economically. Furthermore, when p-1-benzyl chloride is brominated according to the method of the present invention, some of the chlorine of p-t-benzyl chloride may be replaced with bromine, but this violates the purpose of the method of the present invention. isn't it. Also, Tokukai Sho 5
Regarding the halogenation of p-t-butyltoluene with bromine chloride as shown in No. 7-54131, the selectivity of bromine chloride to each of the three hydrogens of the methyl group is not uniform, especially to the final hydrogen atom. The reaction of bromine chloride involves a complex process, which may pose problems in its production.

The crude intermediate p-1-benzal halide obtained according to the present invention has a composition as in conventional methods.

■ ■ ■ Compound of ■ is 5-8%, target compound of ■ is 86-88%
, 1 to 3%, and as is clear from the following examples, the total amount of halogen converted to aldehyde is 9%.
Reach 0% or more.

The gist of the present invention is as follows: D-t-'7-methylbenzyl chloride is obtained by brominating D-t-'7 methylbenzyl chloride with approximately equal moles of bromine, for example, 0.9 to 1.1 moles, at a reaction temperature of, for example, 100 to 200°C. P-t-butylbenzal halide, mainly composed of pt-butylbenzalchlorobromide, is hydrolyzed with approximately equimolar amounts of water at a temperature of, for example, 105 to 125° C. in the presence or absence of a catalyst. The present invention relates to a method for producing pt-butylbenzaldehyde.

In carrying out the present invention, D-t-butylbenzyl chloride can be easily obtained by chloromelizing t-butylbenzene. A manufacturing method according to claim (1).

The above bromination reaction can also be carried out by reacting pt-butylbenzyl chloride with bromine, with or without mercury lamp irradiation, or in the presence or absence of other free radical forming agents. can.

The above hydrolysis reaction involves hydrolyzing pt-butylbenzal halide using water in which about 2.0% of ferric chloride is dissolved, or using metal chloride, organic acid, mineral acid, etc. can be carried out in the presence of a catalyst.

In carrying out the present invention, unreacted p-t-butylbenzyl chloride during the above bromination reaction is
By subjecting t-butylbenzaldehyde to an oxidation reaction, the yield of pt-butylbenzaldehyde can be improved.

For this purpose, 1 mol of unreacted pt-butylbenzyl chloride is treated with approximately 0.5 mol of hexamethylenetetramine at pH 4 to 4.5 to convert pt-butylbenzyl chloride into p- It may be oxidized to t-butylbenzaldehyde.

In addition, in order to increase the purity of the target pt-butylbenzaldehyde, pt-butyl, which is a by-product contained in the crude pt-butylbenzaldehyde obtained by saponifying pt-butylbenzotrihalide, can be used as a by-product. It is sufficient to remove benzoic acid, and for this purpose, crude D-t-butylbenzaldehyde is treated by adding an aqueous solution of sodium carbonate up to P)-19, and then the produced pt-butylbenzaldehyde is separated by fractional distillation. .

Example 1 t-Butylbenzene is produced by a conventional method by reacting benzene and isobutylene, and from this pt-butylbenzyl chloride is produced by a general chloromethylation method to produce pt-butylbenzyl with a purity of 98% or more. Chloride was brominated.

364 gr (2 moles) of pt-butylbenzyl chloride was placed in a turning flask, one neck of which was equipped with a mercury lamp of about 100 W, and the temperature was raised with stirring until the internal temperature reached 120.
℃. Then, 2 moles of bromine (320 gr) was added dropwise into a reflux condenser equipped with 2 moles of bromine at a rate that did not cause brownish brown color. The internal temperature was constantly maintained at 120℃ to 1:25℃ for 7 hours. The dropping process was completed at , and continued at the same temperature for another 30 minutes.
The total amount of cold welding was weighed to give 535 gr of a viscous oil which contained some crystals. The composition of this product is determined by G/C: pt-butylbenzyl chloride 5.8% pt-
Butyl benzal halide 88.4% pt-butyl benzotrihalide 3.5% The halogen distribution of this material was 13.11% chlorine and 29.24% bromine.

Add a solution of 40 cc of water and 0.8 g of Fe C, e3 to the above substance while checking the generation of HBr and IC to perform hydrolysis. After washing with water, do not undergo hydrolysis with water. Add 0.5 mol of the corresponding hexamine to p-t-butylbenzyl chloride, adjust the pH to 4 with an aqueous Na2COa solution, and oxidize at 100-110°C to obtain p-t-butylbenzyl chloride.
Convert t-butylbenzyl chloride to pt-butylbenzaldehyde. The total amount of aldehydes is approximately 9
This amounted to 4%. In order to remove pt-butylbenzoic acid produced by hydrolysis of pt-butylbenzotrihalide in this hydrolysis solution, the oil layer treated with 5% Na2CO3 solution was distilled under reduced pressure (3~ 4 TOrr) Sheet C88~
Collect materials that have a boiling point of 90℃ and call them products. The yield was 294.09.

Yield 1294.09 = Yield 90.9% (from pt-butylbenzyl chloride) Example 2 The bromination of pt-butylbenzyl chloride produced in Example 1 was carried out using the same apparatus as in the previous example. However, this example did not use a mercury lamp, but instead used azobisisobutyronitrile and benzoyl peroxide chloride as radical formers.

That is, 364 gr (2 moles) of pt-butylbenzyl chloride is brominated with 2 moles of bromine (320 gr).

However, at this time, 2 g of azobisisobutyronitrile and 1.5 g of benzoyl peroxide chloride were added, and the bromination was completed in 6 hours at a bromination temperature of 140 to 150°C, and treated in the same manner as in Example 1. , brown viscous oil mixed with crystals 54
5g was obtained. The following composition was obtained: 2.6% pt-benzyl chloride, 80.2% pt-benzal halide, 1.4% pt-benzotrihalide. The obtained viscous liquid was sequentially treated in a conventional manner, and p-t-butylbenzoic acid was added, and the amount of aldehyde in the oil layer was estimated by G/C to be 81.4% p-
Contains t-benzaldehyde. p- which was chemically synthesized from p-1-butylbenzotrihalide treated by a conventional method
A dilute acid was added to sodium t-butylbenzoate to obtain 18.39 pt-butylbenzoic acid. When crude pt-butylbenzaldehyde in the oil layer is distilled under reduced pressure by a conventional method, 23
8.4 gr of 98% pure pt-butylbenzaldehyde was obtained.

Yield 238.4 g = Yield 73.6% (from pt-butylbenzyl chloride) Example 3 The pt-benzyl chloride prepared according to Example 1 is treated in a conventional manner. That is, 364 gr (2 moles) of pt-benzyl chloride was brominated with 2 moles of bromine (320 gr) using only heat without using a mercury lamp or radical former. Bromination temperature is 1
It was dropped into a reflux condenser at a temperature of 60 to 180°C (at a rate that no bromine color was noticeably observed), and the time required for bromination was approximately 6 hours and 30 minutes. 555 g of a thick, viscous brown liquid was obtained, the composition of which was estimated by G/C as follows:

pt-benzyl chloride 3.4% pt-benzal halide 83.3% pt-benzotrihalide 10.4% Other substances 5.1% The above composition was sequentially prepared by the method of Example 1. After careful treatment, p
-The oil layer from which pt-butylbenzoic acid, which is chemically formed from t-benzotrihalide, is removed, is distilled under reduced pressure to produce 98% pure pt-butylbenzaldehyde at 246.8S.
I got F.

Yield 246.89 - Yield 76.2% (from p-butylbenzyl chloride) Comparative Example Using the same equipment under the same conditions as Example 1, the remaining methyl groups were further removed with chlorine without using bromine. Halogenated with two hydrogen atoms. That is, 364 g of pt-benzyl chloride
The reaction was carried out by introducing 2 moles of chlorine at a temperature of 140 DEG to 145 DEG C. for about 4.5 hours. The reaction product was a brown heavy liquid, and the yield of the composition was 425 g. As a result of the G/C inspection of this composition, it was found that there were many unknown substances and the composition ratio was 78.5%, which is considered to be as follows.

l-1a Ha Cto13 H3 The halogens in the above crude products are halogens related to saponification, and the other halogen compounds are presumed to be terminally saponified halogens, but triclide, which is a halogen substituted product of the tertiary butyl group, is Saponified. As a result of estimation of the above composition by G/C, p
-t-Benzyl chloride was O, so it was immediately hydrolyzed using a conventional method, pt-butylbensitrichloride was removed as pt-butylbenzoic acid, and the brown oil was precisely separated under reduced pressure. Although it was collected, it was difficult to separate it from the halogen-substituted product of the tertiary butyl group, and the yield was 220 g of pt-butylbenzaldehyde with a purity of 85%. Since this product contains other chlorine-substituted benzaldehydes, the actual yield was 182.59. Yield 85%
pt-benzaldehyde 2209 = theoretical yield 68.7

Claims (1)

[Scope of Claims] (1) p-1-butylbenzal mainly composed of p-t-butylbenzal chlorobromide obtained by brominating p-t-butylbenzyl chloride with approximately equimolar bromine. A method for producing pt-butylbenzaldehyde, which comprises hydrolyzing a halide in approximately equimolar amounts of water in the presence or absence of a catalyst. (2) The production method according to claim (1), wherein the pt-butylbenzyl chloride is obtained by chloromerizing t-butylbenzene. (3,) The production method according to claim (1) or (2), in which 0.9 to 1.1 moles of bromine is applied per mole of pt-butylbenzyl chloride. (4) 100-200℃ in the presence or absence of a solvent
The method according to any one of claims (1) to (3), wherein bromine is allowed to act on pt-butylbenzyl chloride at a reaction temperature of . (5) p-t with or without irradiation with mercury or in the presence or absence of other free radical formers;
- The manufacturing method according to any one of claims (1) to (4), in which bromine is reacted on butylbenzyl chloride. (6) Hydrolysis of pt-butylbenzal halide to 1
Claim No. (1) carried out at a temperature of 05 to 125°C
The manufacturing method according to any one of paragraphs to (5). (7) Claims (1) to (6) in which p, -t-butylbenzal halide is hydrolyzed using water in which approximately 2.0% ferric chloride is dissolved. ) The manufacturing method described in any one of the preceding items. (8) Hydrolysis of pt-butylbenzal halide,
The manufacturing method according to any one of claims (1) to (7), which is carried out in the presence of a metal chloride, an organic acid, a mineral acid, or other catalyst. (9) In the presence of a catalyst, p-1-butylbenzyl halide mainly consisting of p-t-butylbenzalchlorobromide obtained by brominating p-t-butylbenzyl chloride with approximately equimolar bromine In producing pt-butylbenzaldehyde by hydrolysis with approximately equimolar amount of water in the presence or absence of water, unreacted p-1-
A method for producing pt-butylbenzaldehyde, which comprises subjecting butylbenzyl chloride to a reaction of oxidizing it to pt-butylbenzaldehyde. (10) Unreacted pt-butylbenzyl chloride 1
Claim No. 1, wherein p-1-butylbenzyl chloride is oxidized to p-t-butylbenzylbenzaldehyde by treatment at pH 4 to 4.5 using approximately 0.5 mol of hexamethylenetetramine per mole. 9) Manufacturing method described in section 9). (11) El-t-Butylbenzyl chloride was brominated with approximately equimolar bromine to produce p-1-butylbenzal halide mainly composed of ρ-[-butylbenzalchlorobromide in the presence of a catalyst. In producing pt-butylbenzaldehyde by hydrolysis with approximately equimolar water in the presence or absence of pt-butylbenzaldehyde, pt-butylbenzotrihalide is added to the resulting crude pt-butylbenzaldehyde. A method for producing p-1-butylbenzaldehyde, which comprises removing p-t-butylbenzoic acid contained as a by-product by saponification. (12) The production method according to claim (11), wherein an aqueous sodium carbonate solution is added to the crude pt-butylbenzaldehyde until the pH reaches 9, and then the produced pt-butylbenzaldehyde is separated by fractional distillation.